Refrigerating apparatus



May 18, 1937- n A. T. sTocK y 2,080,749

l REFRIGERATING APPARATUS y I Filed March 7, 1935 2 sheets-sheet 2 Elfil 60 l 48 l l INVENTct/ v ATTORNEYS Y Patented May 18, 1937 2,080,749REFRIGERATING APPARATUS Anthony T. Stock, Muskegon, Mich., assignor toThe Brunswick-Balke-Collender Company, Chicago, Ill., a corporation ofDelaware Application March 7, 1935, serial No.9,7o4

4 Claims. (Cl. 62-127) This invention relates to refrigerating apparatusand more particularly concerns improvements in expansion and evaporatingmechanisms for refrigerating systems.

In refrigerating systems, and particularly those of the type used tocool fluids, such as drinking water and other beverages which aresubject to continuous or intermittent draft, itis desirable that therefrigerant in liquid form be evaporated in direct heat exchangingcontact with the coils carrying the fluids to be cooled. It is furtherdesirable that the temperature to which the draft liquid is cooled beheld within reasonable limits by automatic control mechanism. In manyinstallations, such as fountain, bar or counter coolers, it is essentialthat the cooling apparatus occupy a relatively small space.

With the above and other considerations in mind, it is the object of thepresent invention to provide a refrigerating system embodying improvedcompact and unitary expansion and evaporating mechanism, together withimproved control means for governing the supply of refrigerant to theevaporating chamber. A particular 0bjectof the invention is theprovision of an evaporator, an expansion valve and control meanstherefor which constitute a single unitary structure combining theadvantages of direct evaporation of the liquid refrigerant on the bodyor surface to be cooled with accurate and automatic control of thetemperature of the cooled body or surface. The improved evaporating andexpansion mechanism is particularly applicable to beverage coolers, butthe invention, in its broader aspects, is not limited to thisapplication.

In general, the above and other objects of the invention are carried outby providing a suitable evaporator chamber and by locating therein anexpansion valve which controls thevflow of liqueed refrigerant to theevaporator chamber and further directs the refrigerant in the form ofliquid streams or sprays into contact with the beverage cooling coil orother body or surface to be cooled. The expansion valve isautomaticallyl controlled in accordance with the temperature of theevaporator chamber or of the liquid, surface or body to be cooled, andin a preferred form of the invention, the valve mechanism is soconstructed and arranged that the flow of liquid refrigerant aids inproperly closing the valve when the required amount of liquidVrefrigerant has been admitted to the evaporator chamber. The opening andclosing of the expansion valve is preferably effected by a diaphragm orequivalent expansible means actuated by changes in the pressure of a'thermally' expansible fluid. The pressure chamber including thediaphragm or equivalent means is connected through a suitable duct to abulb or equivalent` means responsive to the temperature of the draftliquid or other surface or body to be cooled or to the temperature ofthe evaporator chamber. In accordance with the invention, although theexpansion valve tained in a very compact structure, while at the sametime, the isolation of the expansion valve operating pressure ychamberfrom the evaporator chamber prevents erratic operation of the expanlsion valve control means.

The invention will be best understood by reference to the accompanyingdrawings in which certain embodiments thereof have been illustrated. Inthe drawings;

Figurel isa diagrammatic elevation of a refrigerating'system embodyingthe invention', certain parts being shown in section to disclose theinterior construction thereof ;v

Figure 2 is an enlarged sectional View of the expansion valve mechanismshown in Figure 1;

Figure 3 is an enlarged plan view ofthe temperature responsive bulb ofthe system; and

Figure 4 is a partial sectional view of a modied form of expansion valveoperating means.

Referring to the drawings, and more particularly to Figure l, the systemthere disclosed asl embodying my invention comprises `generally arefrigerant compressing and condensing unit C and an evaporatorchamberor low-side E. 'I'he refrigerant compressing and condensing unit maytake any suitable known form, and as shown, comprises a compressor 5`driven by a motor 6 and connected to discharge compressed refrigerantinto a condenser 1. The intake 8 of the compressor Sis connected t0 thesuction line 9 from the evaporator E, and the outlet l0 of thecompressor is connected to the inlet of the condenser 1 through the pipeI3. The outlet of the condenser 1 is connected through a liquidcollecting chamber to the refrigerant supply line I2 leading back to theevaporator E.

The compressor of the unit C preferably operaies intermittently and maybe automatically started and stopped`by any suitable control meansresponsive to the temperature of or pressure within the evaporator E orthe pressure vwithin the suction line 9. In the disclosed embodiment, apressure operated switch S, connected to the suction line 9 is employedto control the operation of the compressor driving motor 6. This switchacts in a manner known in the art to close the circuit between the motor6 and a source of electric power I4 when the pressure in the suctionline 9 rises above a predetermined value, and to open this circuit andso stop the compressor when this pressure drops below a predeterminedvalue. The switch S may also be arranged to open the motor circuit iffor-any reason a dangerous or excessive pressure is built up by thecompressor and to this end, a pressure connection |5 is provided betweenthe compressor outlet I andthe switch S.

The above described refrigerant compressing and condensing unit Coperates in the usual and well known manner, drawing gaseous refrigerant.from the suction line 9, compressing it in the "f compressor andcooling and liquefying the outer section 22 and downwardly through the.

`compressed gas in the condenser 1. 'Ihe liqueiied refrigerant collectsin the chamber and passes through the pipe |21 to the evaporator E.

The evaporator chamber E may take any suitable form, and as shown, maycomprise a vertically disposed chamber of cylindrical section havingupper `and lower end walls I6 and |1. In the disclosed embodiment, theevaporator is employed to cool a liquid subject to draft, andaccordingly, a coil O is disposed in the evaporator iiamber E throughwhich the liquid to be cooled passes. The ends of the coil O passthrough sealed openings in the wall |1 of the chamber, and the inlet endi9 thereof is connected to the source of liquid to be cooled, which maybe a beverage reservoir or the mains of a drinking water supply system.The outlet end of the coil O is provided with a tap or faucet 2| forcontrolling the draft of cooled liquid. The coil O shown in the,disclosed embodiment comprises a. plurality of vertical cylindricalsections 22 and 23, and the liquid passes upwardly through the innersection 23. A hollow central core or baille 24 is suitably supportedwithin the inner coil .section 23 and is provided with an outwardlyinclined inwardly extending ilange 25 at the upper edge thereof asshown. An outer cylindrical baffle 2G preferably surrounds the coil Obetween the outer section 22 and the cylindrical wall of the evaporatorchamber E. 'Ihe baiiles 24 and 26 serve to confine the liquidrefrigerant introduced to the evaporator chamber to the portion of thechamber occupied by the coil O.

n Liquelied refrigerant from the chamber 4|| is conducted into theevaporator chamber E by the pipe 2 which is sealed through an opening inthe lower end wall |1 ofthe evaporator. In accordance with theinvention; the expansion valve of the system is disposed withinandarranged to discharge liquidrefrigerant directly into the Ainteriorof the evaporator chamber E. The ex' pansion valve proper may besupported by any i suitable means and as shown,-` a circular supportingplate 21 carried by posts, 28 fixed to the upper'end wall I5 is providedfor vthis purpose.

'evaporator chamber in various ways.

34' in the central bore 30 of the body 29. The

recess 33 in the plunger 3| is connected through the transverse passages42 to a valve chamber 43 surrounding the upper end of the plunger. Theupper end of the plunger 3| is provided with a shallow circular recesscarrying a valve member comprisinga thin circular disc 44. The upper endof the valve body 29 is closed by a plug 45 having a central dischargeorice 46 therethrough.v Annular valve seats 41 are formed on thelower'surface of the plug 45 about the oriiice 46 for engagement by thevalve memberbr disc 44 when the valve is closed. A valve operating rod48 passes loosely through the orifice 46 and is engageable with thecenter of the disc 44. The liquefied refrigerant pipe |2 is suitablyconnected to the central bore 30 of the expansion valve body 29 by aunion 49.

From the description given, it will be apparent that when the operatingrod 48 is pressed inwardly through the orifice 46, the disc 44 is' movedfrom its seat 41 against the resistance of the spring 32, and liquidrefrigerant iiows out through the orifice 46 along the surface of theloperating rod-48.

The expansion valve is preferably operated to admit liquid refrigerantto the evaporator chamber E by the expansion of a pressure expansiblechamber and the pressure in this chamber is varied in accordance withchanges in the evaporator chamber. In the disclosed embodiment, thetemperature responsive element in the evaporator chamber comprises abulb 50 disposed about a portion of the inner section 23 of the liquidcoil O, and is thus responsive to the temperature of the coil and. thetemperature of the interior of the evaporator chamber E. The bulb 50carries a suitable thermally expansible fluid which may be in gaseousform or may be partly in liquid form and partly gaseous. For the purposeof illustration, a body of readily volatilizable liquid 5| has beenshown in the bulb 5|).

Inaccordance with the invention, it is preferred dense and/or contractin the pressure chamberl and thus counteract the expansion of such fluidin the bulb, and erratic control operation with wide temperaturevariations would result.

' The pressure expansible valve operating charnber may be isolated fromthe interior of the Thus, as shown in Figure 1, the pressure chamber maybe formed within an end wall I6 of the evaporator 'chamber E, and sincewith the refrigerating system in operation, the interior of theevaporator chamber andthe liquid 'coil O therein are at all times coolerthan the surrounding atmosphere,

the pressure chamber in the evaporator wall will wall I6 and a flexiblediaphragm 53 is disposed in spaced relation to the inner face of thisrecess, thus defining a pressure chamber 54. The pressure chamber 54 anddiaphragm 53 are isolated from the interior of the evaporator chamber Eby a plate 52 which also serves to seal the diaphragm in place. Theplate 52 may be sealed within the recess inthe wall I6 by suitable meanssuch as solder, as indicated at 55. The bulb is connected to thepressure chamber 54 by a pipe 56 which passes through the wall I6 andVcommunicates with the chamber 54 through an opening 51 in the wall I6as shown. A sealed charging tube 58 communicates with the pressurechamber 54 through the wall I6. The movement of the flexible diaphragm53 in response to pressure changes in the chamber 54 is transmitted tothe operating rod 48 of the expansion Valve by a plunger 59- slidablycarried in a central opening through the plate 52.

In accordance with the invention, means are provided on the valveoperating mechanism for deflecting the stream of liquid refrigerantdischarged from the valve orifice 46 into a spray which comes intodirect contact With-the liquid coil O or other body or surface to becooled.

Thus, as best shown in Figure 2, a deflector 66 is attached to or formedintegral with the operating rod 48 and extends radially outwardtherefrom. The deflector 60 may comprise an integral part with theplunger 59 or may be suitably secured thereto as desired. The lower faceof the deector 6D is preferably concave or dished as shown at 6I. Withthis arrangement, the liquid refrigerant stream flowing along the rod 48when the expansion valve is open strikes the concave end surface 6I ofthe defiector 60 and is sprayed radially outward in a spray whichimpinges directly on the surrounding coil O. The path taken by theliquid refrigerant is indicated by the ari rows in Figure 2.

The deflector 60 not only serves as an effective means for breaking upthe liquid refrigerant and directing it against the liquid coil, butalso aids in properly closing the expansion valve. Thus when thepressure within the chamber 54 drops to a predetermined point, due to adrop in the temperature of the bulb 50 to a value slightly above theminimum value required, the spring 32 and the reaction of the liquidrefrigerant impinging on the deflector 60 combine to move the operatingrod 48 upwardly, and the valve disc 44 is seated to cut olf the flow ofliquid refrigerant. When the valve disc 44 is seated, the force of theimpinging refrigerant is no longer applied to the v operating rod, butthe continued reduction in temperature of the evaporator, due to thecontinued evaporation of refrigerant therein while the valve moves toits closed position, reduces the pressure in the chamber 54 to a valuebelow that capable of reopening the Valve against the resistance of thespring 32. Thus the expansion valve starts to close just beforesuiiicient refrigerant has been admitted to the evaporator chamber, and

the admission of excess `quantities of refrigerant to the evaporator isavoided.

It is usually preferred to employ a pressure regulating kvalve intheevaporator suction line to aid in maintaining a substantially constanttemperature in the evaporator chamber E and such a valve is shown at Pin the pipe 9. The valve P may be of any suitable construction capableof maintaining a substantially constant pressure in the evaporatorvE.AAs shown, the valve member 34 of the Valve P is operated by a bellows35r exposed on one side to the pressure in the evaporator E and on theother side to atmospheric pressure and the pressure of a variablyadjusted spring 36. The spring pressure may be A,varied by rotation of`the threaded sleeve 31 which raises or lowers a spring abuttingnut 38,held against rotation with the sleeve 31 by a rod 39. A central threadedstem 40 is provided forclosing the valve when the system is not in use,and the spring adjusting sleeve 31 is held against accidental movementby a lock nut 4I. With the arrangement described,an increase inpressurein the evaporator chamber beyond ak predetermined point compresses thebellows 35 against the spring 36 and so opens the valve 34 andpermitsthe escape of sufficient refrigerant gas to lower theevaporatorpressure'to the desired point.

In a modified form of the invention shown in i Figure 4, the pressureexpansible chamber which operates the expansion valve is located outsideof the wall of the evaporator chamber; Thus theupper end wall I6lcarries a centrally apertured tting'62 threaded or otherwise suitablysealed in a central opening through the wall I6 as shown. A cap r63having ari annular recess 64 therein extends over the edges oftheoutwardly extending flange 65 on the fitting 62, and a flex` iblediaphragm 66 is disposed between the edges of the iiange 65 and the cap63. The sealed joint 61 of solder or the like unites the cap 63, theflange 65 and the diaphragm 66. The, annular recess 64 forms a pressureexpansible chamber between the cap 63 and the diaphragm 66, and a pipe56l connects this chamber with the bulb 5I) within the evaporatorchamber. -A sealed charging tube 68 may be provided for thepressurevchamber 64. The diaphragm 66 acts on a plunger 69 slidablysupported in the central aperture through the fitting 62, and the lowerend of this plunger is suitably connected tothe deilector 60 and thevalve operating rod 48' within the evaporator chamber. The rod 48Voperates the expansion valve in the manner described above in connectionwith Figures 1 and 2.

In the operation of the disclosed embodiments of the invention, theinlet I9 of the coil O is connected to a source of the liquid to becooled and l the refrigerant compressor 5 is started. Liquefiedrefrigerant collects in the chamber I I and is delivered to theevaporator chamber E through the pipe I2, the expansion ,valve beingopen at this point due to the comparatively high temperature in theevaporator chamber. The liqueed refrigerant is .sprayed on to the coil Oby the deflector 60 of the expansion valve mechanism', and

this refrigerantv evaporates as it passes down over the coil O betweenthe bailles 24 and 26. The evaporated refrigerant is withdrawn from theevaporator chamber E through the suction line 9. T'hevevaporation of theliquid refrigerant cools the coil O and when the desired low temperaturehas -been obtained, the pressure in the evaporator chamber E falls tothe point where the valve P closes. As the evaporator tempera# I tureapproaches the desired minimum temperature, but before this temperatureis reached, the contraction or condensation of the thermally sensitiveuid 5I in the bulb 50 results in the closing of the expansion valve inthe manner described above. The evaporation of the remaining liquefiedrefrigerant in the evaporator chamber reduces the evaporator temperatureto the desired low point at which the valve P closes.

When the valve P is closed, the pressure in the suction line 9 isquickly reduced by the com.

pressor 5 to a point where the pressure operated switch S Opens andstops the compressor.

When the cooled liquid is drawn from the coil O, the uncooled liquidadvancing through this coil heats the bulb 50, expands and/or evaporatesthe thermally sensitive fluid 5| therein and thus opens the expansionvalve and admits liqueed refrigerant to the evaporator chamber E. Theevaporation of this liquid'cools the coil O to the desired temperature,and the expansion valve is yagain closed, as explained above. Thesuction line valve P opens to permit the ow of evaporated refrigerantuntil the desired low temperature is reached. Whenever the pressure inthe suction line 9 rises aboveia predetermined value, the switch S isclosed and the refrigerant cornpressing and condensing apparatusoperates to replenish the supply of ,liquefied refrigerant in thechamber H.

Although the invention has been described in connection with a draftliquid cooler, it should be understood that the invention is not limitedto this application and that the improved expansion and evaporatingmeans may be employed in the usual refrigerator cooling units andgenerbody, a spring acting to force the plunger upwardly, the upper endof the plunger being provided with a shallow circular recess, and avalve member comprising a thin circular disc in the recess.

2. A refrigerating expansion device comprising a hollow valve body, aplunger slidable in the body, a spring acting to force the plungerupwardly, the upper end of the plunger being prol vided with a shallowcircular recess, and a valve member comprising a thin circular disc in te recess, together with a plug closing. the upper e d oi the valve body,said plug having a central di charge orice therethrough.

3. A refrigerating expansion device comprising a hollow valve body, aplunger slidable in the body, a spring acting to force the plungerupwardly, the upper end of the plunger being provided with a shallowcircular recess, and a. valve member comprising a thin circular disc inthe recess, together with a plug closing the upper end of the valvebody, said plug having a central discharge oriilce therethrough, anannular valve seat formed on the lower surface of the plug about saidorifice for engagement by the valve member when the valve is closed.

4. A refrigerating expansion device comprising a hollow' valve body, aplunger slidable in the body, a spring acting to force the plungerupwardly, the upper end of the plunger being provided with a shallowcircular recess, and a valve member comprising a thin circular disc inthe recess, together with a plug closing the upper end of the valvebody, said plug having a central discharge orifice therethrough, anannular valve seat formed on the lower surface of the plug about saidorifice for engagement by the valve member when thevalve is closed, anda valve operating rod passingloosely through the orifice and engageablewith the center of the disc.

ANTHONY T. STOCK.

